Protecting Canada’s precious freshwater resources

NRC modeling tools help communities manage flooding and drought risks

December 05, 2017— St. George, New Brunswick

High flows during the April 2014 flood event on the Magaguadavic River.

The National Research Council (NRC) works with communities across Canada to reduce the potentially devastating impacts of floods and droughts, and to protect this country’s abundant freshwater resources.

Canada’s vast freshwater resources make a significant contribution to national prosperity. Lakes and rivers provide Canadians not only with drinking water, food, transportation networks and recreational opportunities, but also with hydroelectricity. In fact, Canada is one of few countries around the world to rely on hydropower for more than half of its electricity needs.

Making the most of Canada’s freshwater resources is a formidable challenge, one that involves balancing local water demands that may change throughout the year, with local water supplies that may fluctuate quickly in a way that are difficult to anticipate and predict. For example, a local oversupply of water caused by rapid snowmelt combined with intense rainfall may lead to catastrophic flooding. The need to balance the conflicting demands of various water users adds to the water management challenge. Canadian water managers rely on vast, complex networks of more than 10,000 dams, reservoirs and diversions to help them meet this challenge.

In recent years, several regions in Canada have experienced unusual weather patterns, such as intense storms and lengthy droughts. Climatologists predict that severe weather will become more frequent and common in the future. The social, environmental and economic impacts are expected to be significant.

To help meet this challenge, the NRC collaborates with other government departments and industry partners to improve the management of water resources. The NRC has created a series of sophisticated modelling and visualization tools to increase its understanding of how river systems interact with dams, reservoirs and other man-made structures.

Modelling water flow in river systems

Dam operations have limited effect on upstream water levels on the Magaguadavic River due to the presence of submerged flow restrictions.

Rainy River is located in northwestern Ontario and runs along Canada’s border with the United States. A dam on the river helps to regulate water levels and maximize the efficiency of a major hydro-generating facility. The dam’s operations affect the levels of Rainy Lake and other bodies of water. Tourism is a major industry in the region; thousands of visitors come here each summer to fish, explore and play in the region’s many beautiful lakes, rivers and forests. As a result, many residents are concerned about the dam’s impacts on water levels – in particular about the dam’s role in upstream flooding.

The NRC experts created a detailed, two-dimensional numerical model of the river system and studied the relationship between dam operations – such as the number of floodgates open – and the levels of nearby rivers and lakes. The research determined that the dam was only one of various factors that influence water levels and flow rates. A natural constriction upstream of the dam, for instance, can also limit water flows. To help explain these findings to the community, the NRC created an online interactive visualization tool that displays results from its detailed computer simulations through an intuitive user-friendly interface. The new visualization tool enables community members to view the impacts of opening or closing dam gates for a wide range of realistic scenarios.

A similar NRC project in southwestern New Brunswick shed new light on the impacts of the St. George dam on the flows and levels in the Magaguadavic River. As in Rainy River, the dam is essential to the operation of a hydroelectric facility. However, the New Brunswick facility has no reservoir. Instead, the river’s natural flow turns the dam’s turbines in a process known as run-of-the-river power generation.

In December 2010, heavy rains triggered significant floods in this part of New Brunswick, causing severe damage. To identify the dam’s impacts on flow rates and water levels, dam owner J.D. Irving Ltd. commissioned the NRC to develop a detailed 2D hydrodynamic model of the river system and investigate the relationship between dam operations, flows, and upstream water levels. The NRC researchers also created an online interactive visualization tool to present their simulation results and inform the local community. The company now uses the NRC’s model and visualization tool to optimize the dam’s operation.

The future of watershed management

In an era of rapidly shifting climate patterns, sophisticated modeling and simulation tools will become increasingly important to the management of freshwater resources. Effective management requires careful consideration of a wide range of factors – from the operations of dams and hydro-electric facilities, to ground-saturation levels, water flows and river levels. When used properly, the NRC-developed models and tools can predict the impacts that an early-spring melt or an intense summer rainstorm would have on nearby communities and on the entire watershed.

The NRC continues to work on a number of processes and technologies that promise to mitigate the potentially harmful impacts of extreme weather events. One additional area of focus is incorporating climate resilience into the design of buildings and core public infrastructure. This research, along with decades-long expertise in developing solutions to engineering challenges within river environments, aims to protect Canadians’ quality of life.

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